/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2013, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.rolling.helper;

import java.io.File;
import java.io.FilenameFilter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class FileFilterUtil {

  public static void sortFileArrayByName(File[] fileArray) {
    Arrays.sort(fileArray, new Comparator<File>() {
      public int compare(File o1, File o2) {
        String o1Name = o1.getName();
        String o2Name = o2.getName();
        return (o1Name.compareTo(o2Name));
      }
    });
  }

  public static void reverseSortFileArrayByName(File[] fileArray) {
    Arrays.sort(fileArray, new Comparator<File>() {
      public int compare(File o1, File o2) {
        String o1Name = o1.getName();
        String o2Name = o2.getName();
        return (o2Name.compareTo(o1Name));
      }
    });
  }

  public static String afterLastSlash(String sregex) {
    int i = sregex.lastIndexOf('/');
    if (i == -1) {
      return sregex;
    } else {
      return sregex.substring(i + 1);
    }
  }

  static public boolean isEmptyDirectory(File dir) {
    if (!dir.isDirectory()) {
      throw new IllegalArgumentException("[" + dir + "] must be a directory");
    }
    String[] filesInDir = dir.list();
    if (filesInDir == null || filesInDir.length == 0) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * Return the set of files matching the stemRegex as found in 'directory'. A
   * stemRegex does not contain any slash characters or any folder separators.
   *
   * @param file folder's file object
   * @param stemRegex regex file pattern to match
   * @return matching files
   */
  public static File[] filesInFolderMatchingStemRegex(File file,
      final String stemRegex) {

    if (file == null) {
      return new File[0];
    }
    if (!file.exists() || !file.isDirectory()) {
      return new File[0];
    }
    return file.listFiles(new FilenameFilter() {
      public boolean accept(File dir, String name) {
        return name.matches(stemRegex);
      }
    });
  }

  static public int findHighestCounter(File[] matchingFileArray, final String stemRegex) {
    int max = Integer.MIN_VALUE;
    for (File aFile : matchingFileArray) {
      int aCounter = FileFilterUtil.extractCounter(aFile, stemRegex);
      if (max < aCounter)
        max = aCounter;
    }
    return max;
  }

  static public int extractCounter(File file, final String stemRegex) {
    Pattern p = Pattern.compile(stemRegex);
    String lastFileName = file.getName();

    Matcher m = p.matcher(lastFileName);
    if (!m.matches()) {
      throw new IllegalStateException("The regex [" + stemRegex
          + "] should match [" + lastFileName + "]");
    }
    String counterAsStr = m.group(1);
    return Integer.valueOf(counterAsStr);
  }

  public static String slashify(String in) {
    return in.replace('\\', '/');
  }

  public static void removeEmptyParentDirectories(File file,
      int recursivityCount) {
    // we should never go more than 3 levels higher
    if (recursivityCount >= 3) {
      return;
    }
    File parent = file.getParentFile();
    if (parent.isDirectory() && FileFilterUtil.isEmptyDirectory(parent)) {
      parent.delete();
      removeEmptyParentDirectories(parent, recursivityCount + 1);
    }
  }
}
